Propellant powder and process of making the same



Patented Apr. 23, 1929.

UNITED STATES PATET OFFICE.

ARTHUR S. ONEIL, F ALTON, ILLINOIS, ASSIGNOR TO WESTERN CARTRIDGE COM- IPANY, OF EAST ALTON, ILLINOIS, A CORPORATION OF DELAWARE.

PROPELLANT POWDER AND PROCESS OF MAKING THE SAME.

No Drawing. Original application filed June 20, 1924, Serial No. 721,203. Divided and this application filed October 12, 1925. Serial No. 62,091.

This invention relates to progressive powders and more particularly to progressive burning propellant powders adapted for use in small arms such as shot guns. This application isa division of my application Serial Number 7 21,203, filed June 20, 1924.

Y The rate of burning of a powder is dependent upon its composition. Thus dense colloidcd nitro-cellulose powder has a lower 10 rate of burning than, for instance, a low nitration nitro-cellulose bulk powder or a nitro-glycerin-nitro-cellulose powder.

One of the objects of this invention, therefore, is to provide a progressive burning powder consisting of blended grains, the compositions of which are so chosen as to cause a blended charge thereof to burn progressively.

Another object of this invention is to pro- 'vide a progressive burning powder, consisting of blended portions, each portion having a grain size and composition which is different from that of the other, the characteristics of the several portions being so chosen as to cause a blended charge thereof to burn progressively.

Another object is to provide such a progressive burning powder which is particularly adapted for use as the propellant charge in a shot shell. Further objects will appear from the detail description in which will be disclosed a number of illustrative embodiments of this invention.

In accordance with this invention a powder is produced by selecting powder portions so that the grains of the several portions burn at progressively decreasing rates and the portions so chosen are then blended in the desired proportions so as to produce the desired progressive burning of a blended charge. While the grain compositions of the same portion may be substantially the same, the grain compositions of the several portions vary progressively in accordance with the desired progressive action of a blended charge.

In accordance with an embodiment of this invention,. the rate of burning is controlled by proper selection of the grain composition.

Thus a powder adapted for use in shot gun shells containing heavy shot, such as buck shot, is as tollows:

80% dense colloidcd intro-cellulose powder of high nitration and coated with dinitro-toluene.

20% nitro cellulose-nitrmglycerin powder of low nitration and amounted.

Such a powder has given satisfactory results in high velocity buckshot loads.

An example of controlling the rate of burning by varying both the gram sizes and composltlon is as follows:

90%80% ground smokeless powder (dense eolloided mtro-cellulose, either coated with diuitro-toluene or uncoated) sized as follows:

66%% through 40 mesh on 46. 331A;% through 46 mesh on 70.

10%--20% black powder-3 F. G.

Another example of mixed grain, size and composition is as follows:

00%S0% ground smokeless-same as the preceding powder consisting of v 70% potassium nitrate 15% barium nitrate 15% charcoal. The charcoal (or cellulose) may be impregnated with the potassium nitrate (or sodium nitrate) and the barium nitrate by a soaking and drying process. The above powder in a standard shot shell load gives 1037 foot seconds with 7346 per square inch as against 985 foot seconds with equalpressure when using standard load of dense smokeless powder.

In accordance with this invention, therefore, the progressive burning action is produced by proper selection of the grain compositions of the portions of the blended charge; and by the proper selection of the proportions of the charge portions the desired progressive burning can be obtained. In accordance with thisinvcntion the more rapid burning powders impart their energy directly to the slower burning constituents of the mixture and there is no localizing of pressure but rather a uniform increase in the rate of burning which in turn imparts a sustained drive to the projectile.

In accordance with one embodiment of" this invention, the progressive burning action produced by the proper selection of both grain size and composition and by the ing of proper selection of the portions of the charge, the desired progressive burning can be obtained.

"The progressive burning powder made in accordance with this invention is especially suitable for use in shot shells and such a shell may be constructed and loaded as dis-.

cordingly the rate of combustion will in-,

crease so that the desired pressure is maintained, especially since the heavy wadding provides sufficient resistance to the expansion of the gases to maintain the pressure. The result is, therefore, that the combustion is uniformly accelerated, even after the confining wadding and the shot begin to move, so that. the pressure is maintained nearly uniform for an extended distance along the gun barrel; the result is that the shot charge is uniformly accelerated under a lower initial pressure maintained for an extended distance along the gun barrel.

While in the specification and claims the term grain is used, it is to be understood that it is intended as a word of general description and not of limitation, but to include the various forms in which powder is produced for use. It will be further understood that while theories of formation and operation have been advanced, the invention is not necessarily limited thereto. It will further be obvious that various changes may be made in details without departing from the spirit of this invention; it is, therefore,

to be understood that this invention is not to be limited to the specific details described.

Having thus described the invention, what is claimed is: v

1. A regressive burning powder consistlended grains, the compositions of which are so chosen as to cause a blended charge thereof to burn progressively.

2. A progressive burning powder consisting of blended portions, the grain composition of each portion being different from that of the other, the compositions of the several portions being so chosen as to cause -a blended charge thereof to burn progressively.

3. A progressive burning powder consisting of blended portions, the grain compositions of each portion being substantially the, same but the grain compositions of the several portions being so chosen as to cause a blended charge thereof to burn progressively.

4. A progressive powder consisting of blended grains of different compositions, the grain compositions being so chosen as to cause a blended charge thereof to burn progressively.

5. A progressive burning powder consisting of blended portions, each portion having a grain size and composition which is different from that of the other, the characteristics of the several ortions being so chosen as to cause a blenc ed charge thereof to burn progressively.

6. The process of making progressive burning powder consisting of blending powder portions in which the grain composition of each portion is different from that of the other and so choosing the grain compositions of the several fportions as to cause a blended charge thereo. to burn progressively.

7. The process of making progressive burning powder consisting in blending portions in which the grain composition of each portion is different from that of the other and so choosing the compositions of the several portions and the relative proportions of these portions as to cause a. blended charge thereof to burn progressively.

8. The process of making progressive powder consisting in selecting powder portions so that the grains of the several portions are of progressively diflerent compositions and blending the portions.

In testimony whereof I aflix my signature this'25th day of August, 1925? ARTHUR S. ONEIL. 

